In the field of a photographic plate making, in order to meet the variety and complexity of printed matters, there is a demand for a photographic light-sensitive material having a good original reproducing performance, a stable processing solution, and simplified replenishing.
Particularly in a line photographing process, an original is made by applying a photocomposition character, a hand written character, an illustration, a halftonedotted photograph. Accordingly, images having different densities and line widths are mixed and present in the original, and there is a strong demand for a printing plate making camera, a photographic light-sensitive material, and an image forming method for treating these originals with a good reproducibility. Meanwhile, the scale up or scale down of a halftone dot photograph is broadly carried out during the plate making of a catalogue or a large size poster. In a plate making in which a scaled-up halftone dot is used, lines are toughened and a photographed dot gets vague. In the plate making in which a scaled-down halftone dot is used, the line number/inch ratio is larger than that of the original and the photographed dot gets fine. Accordingly, in order to maintain the reproducing performance of a halftone dot gradation, there is required an image forming method having a broader latitude.
The ultrahard gradation silver halide light-sensitive materials of a multi-layer structure having a layer containing a redox compound releasing a development inhibitor upon oxidation and a light-sensitive silver halide emulsion layer containing a hydrazine derivative are disclosed as a method for improving the reproducing performance of an original in JP-A-1-108215 (the term "JP-A" as used herein means an unexamined published Japanese patent application) and 1-240967.
However, light-sensitive materials including these combinations have a large variation in the photographic characteristics such as sensitivity and Dmax values due to fatigue of the developing solution and therefore an improvement therein is needed.
In a lithographic developing system, it is very difficult to maintain the activity of the developing solution constant, and the instability of image formation due to that feature used to be an important weakness. That requires an image forming system in which development is carried out in a processing solution having a good storage stability and with which an ultrahard gradation photographic characteristic can be obtained. As can be seen in U.S. Pat. Nos. 4,166,742, 4,168,977, 4,221,857, 4,224,401, 4,243,739, 4,272,606, and 4,311,781, there was proposed as one means to meet such requirements, a system in which a surface latent image type silver halide photographic light-sensitive material to which a specific hydrazine compound is added is processed in a developing solution with pH of 11.0 to 12.3 containing a sulfite preservative of 0.15 mole/liter or more and having a good storage stability to form a negative image of an ultrahard gradation having a .gamma. value exceeding 10. However, a large variation in photographic characteristics such as sensitivity and Dmax values due to fatigue of the developing solution still remains great so that it can not be neglected, and various devices have been tried for improvement therein.
Meanwhile, the use in combination of hydrazine compounds each having a different structure or quality is disclosed in JP-A-62-247351, JP-A-62-270948, JP-A-63-249838, JP-A-3-102343, and JP-A-3-152528, and Japanese patent applications 3-128212 and 3-246493.
In none of these methods, however, has compatibility of excellent original reproducing performance and processing stability yet been achieved.